Let's do some math ..  Rounding examples of 7 random hypothetical purchases:
Case	Tag   Price	Sales   Tax %	Raw Total   Incl. Sales Tax	Rounded   to Penny	Rounded   to Nickel	Rounded   to Dime
Purchase #1	$75.35	13.689%	$85.6647	$85.66	$85.65	$85.70
Purchase #2	$153.91	5.583%	$162.5028	$162.50	$162.50	$162.50
Purchase #3	$52.66	12.528%	$59.2572	$59.26	$59.25	$59.30
Purchase #4	$81.79	11.198%	$90.9488	$90.95	$90.95	$90.90
Purchase #5	$161.75	12.239%	$181.5466	$181.55	$181.55	$181.50
Purchase #6	$208.77	13.244%	$236.4195	$236.42	$236.40	$236.40
Purchase #7	$191.44	9.493%	$209.6134	$209.61	$209.60	$209.60
7 purchase totals =	$925.67		$1,025.9530	$1,025.95	$1,025.90	$1,025.90